In IC cards and mobile devices, there are some devices configured in such a manner as to receive supply of electric power by wireless power based on magnetic resonance without incorporating batteries in them. Such a device includes an LC oscillator circuit for magnetic resonance. However, when a value of inductance L or capacitance C deviates from a normal value due to production variation or the like, the LC resonance frequency deviates from the normal value. As a result, there is a possibility of sufficient electric power becoming unable to be received.
In order to prevent the above-mentioned problem from occurring, a procedure in which a plurality of impedance elements for trimming configured to tune the values of inductance L and capacitance C are provided and, in the stage of pre-shipment inspection, trimming of inductance L or capacitance C is carried out is effective.
However, heretofore, it could have hardly been said that a device and method making it possible to carry out a trimming operation at low cost and in a simple way have been proposed.